Validity of an ultra-wideband local positioning system to measure locomotion in indoor sports

The validity of an Ultra-wideband (UWB) positioning system was investigated during linear and change-of-direction (COD) running drills. Six recreationally-active men performed ten repetitions of four activities (walking, jogging, maximal acceleration, and 45º COD) on an indoor court. Activities were repeated twice, in the centre of the court and on the side. Participants wore a receiver tag (Clearsky T6, Catapult Sports) and two reflective markers placed on the tag to allow for comparisons with the criterion system (Vicon). Distance, mean and peak velocity, acceleration, and deceleration were assessed. Validity was assessed via percentage least-square means difference (Clearsky-Vicon) with 90% confidence interval and magnitude-based inference; typical error was expressed as within-subject standard deviation. The mean differences for distance, mean/peak speed, and mean/peak accelerations in the linear drills were in the range of 0.2-12%, with typical errors between 1.2 and 9.3%. Mean and peak deceleration had larger differences and errors between systems. In the COD drill, moderate-to-large differences were detected for the activity performed in the centre of the court, increasing to large/very large on the side. When filtered and smoothed following a similar process, the UWB-based positioning system had acceptable validity, compared to Vicon, to assess movements representative of indoor sports.

Transitional Needs of Australian Young Adults With Type 1 Diabetes: Mixed Methods Study

BACKGROUND

Young adulthood is marked by transitions that impact diabetes self-management behaviors, which require ongoing diabetes education and support. Traditional diabetes education programs and services currently do not meet the needs of many young adults with type 1 diabetes mellitus (T1DM) as they continue to fall through the cracks of clinical services. Age-centered diabetes education programs and services present an opportunity for young adults to meet in a supportive environment and gain a better understanding about diabetes management.

OBJECTIVE

The aim of the study was to identify the health and well-being needs of Australian young adults aged between 18 and 35 years with T1DM to develop appropriate solutions to keep them engaged with diabetes self-management.

METHODS

In total, 13 semistructured individual interviews and self-reported surveys were obtained to understand participants' experiences with diabetes education programs and services. Together with survey data, transcribed interviews were analyzed into themes and categories using comparative analysis to identify the health and well-being needs of young adults with T1DM during young adulthood.

RESULTS

Diabetes education and service needs for young adults with T1DM related to improving access to existing diabetes education programs and services, having credible informational resources, as well as having personalized diabetes management advice. Participants especially valued relevant and real-time information and opportunities for peer support, mostly sourced from Web-based platforms.

CONCLUSIONS

There is a need for diabetes education programs and services to be age-appropriate and easily accessible, to provide relevant and credible information, and to provide opportunities for peer support to better support young adults with T1DM. These findings also support the use of diabetes education programs or services delivered online through mHealth systems in this population.

How to get a nation walking: reach, retention, participant characteristics and program implications of Heart Foundation Walking, a nationwide Australian community-based walking program

BACKGROUND

Community-based walking programs represent a low-cost, accessible approach to increasing physical activity among inactive adults. However, recruiting participants from vulnerable and hard-to-reach groups remains a challenge. This study examined the reach, retention, sociodemographic and health characteristics, physical activity levels and motivators of participants in Heart Foundation Walking, a nationwide Australian community-based walking program.

METHODS

Descriptive cross-sectional analyses were undertaken with data from 22,416 participants aged 15+ years in the Heart Foundation Walking registration database in December 2015, and from four surveys of participants in 2010 (n = 2400), 2011 (n = 3274), 2012 (n = 4158) and 2015 (n = 1890).

RESULTS

Heart Foundation Walking reached participants in every geographic region of Australia, including remote and sparsely populated regions, and engaged sizeable proportions of the following at-risk participants: older than 60 years (>70%); with very low incomes (17-25%); who were overweight or obese (around 60%); and with one or more chronic disease or disease risk factors (57-81%). For all demographic groups, one-year retention rates were at least 75%. Seventy percent of participants met physical activity recommendations. Over 75% reported joining the program for health and fitness reasons while the most cited motivator for continuing was the social aspect (57-73%).

CONCLUSIONS

Volunteer-run, group-based walking programs can have substantial reach and retention, in particular among those at risk for physical inactivity. The provision of opportunities for social interaction appears to be a key program element in promoting long-term participation, including among high-risk groups.

Cluster randomized controlled trial of a consumer behavior intervention to improve healthy food purchases from online canteens

Background: School canteens represent an opportune setting in which to deliver public health nutrition strategies because of their wide reach and frequent use by children. Online school-canteen ordering systems, where students order and pay for their lunch online, provide an avenue to improve healthy canteen purchases through the application of consumer-behavior strategies that have an impact on purchasing decisions.Objective: We assessed the efficacy of a consumer-behavior intervention implemented in an online school-canteen ordering system in reducing the energy, saturated fat, sugar, and sodium contents of primary student lunch orders.Design: A cluster-randomized controlled trial was conducted that involved 2714 students (aged 5-12 y) from 10 primary schools in New South Wales, Australia, who were currently using an online canteen ordering system. Schools were randomized in a 1:1 ratio to receive either the intervention (enhanced system) or the control (standard online ordering only). The intervention included consumer-behavior strategies that were integrated into the online ordering system (targeting menu labeling, healthy food availability, placement, and prompting).Results: Mean energy (difference: -567.25 kJ; 95% CI: -697.95, -436.55 kJ; P < 0.001), saturated fat (difference: -2.37 g; 95% CI: -3.08, -1.67 g; P < 0.001), and sodium (difference: -227.56 mg; 95% CI: -334.93, -120.19 mg; P < 0.001) contents per student lunch order were significantly lower in the intervention group than in the control group at follow-up. No significant differences were observed for sugar (difference: 1.16 g; 95% CI: -0.50, 2.83 g; P = 0.17).Conclusions: The study provides strong evidence supporting the effectiveness of a consumer-behavior intervention using an existing online canteen infrastructure to improve purchasing behavior from primary school canteens. Such an intervention may represent an appealing policy option as part of a broader government strategy to improve child public health nutrition. This trial was registered at www.anzctr.org.au as ACTRN12616000499482.

Associations between major chain fast-food outlet availability and change in body mass index: a longitudinal observational study of women from Victoria, Australia

OBJECTIVES

The residential neighbourhood fast-food environment has the potential to lead to increased levels of obesity by providing opportunities for residents to consume energy-dense products. This longitudinal study aimed to examine whether change in body mass index (BMI) differed dependent on major chain fast-food outlet availability among women residing in disadvantaged neighbourhoods.

SETTING

Eighty disadvantaged neighbourhoods in Victoria, Australia.

PARTICIPANTS

Sample of 882 women aged 18-46 years at baseline (wave I: 2007/2008) who remained at the same residential location at all three waves (wave II: 2010/2011; wave III: 2012/2013) of the Resilience for Eating and Activity Despite Inequality study.

PRIMARY OUTCOME

BMI based on self-reported height and weight at each wave.

RESULTS

There was no evidence of an interaction between time and the number of major chain fast-food outlets within 2 (p=0.88), 3 (p=0.66) or 5 km (p=0.24) in the multilevel models of BMI. Furthermore, there was no evidence of an interaction between time and change in availability at any distance and BMI.

CONCLUSIONS

Change in BMI was not found to differ by residential major chain fast-food outlet availability among Victorian women residing in disadvantaged neighbourhoods. It may be that exposure to fast-food outlets around other locations regularly visited influence change in BMI. Future research needs to consider what environments are the key sources for accessing and consuming fast food and how these relate to BMI and obesity risk.

A pilot intervention to reduce postpartum weight retention and central adiposity in first-time mothers: results from the mums OnLiNE (Online, Lifestyle, Nutrition & Exercise) study

BACKGROUND

Postpartum weight retention (PPWR) increases the risk for obesity and complications during subsequent pregnancies. Few interventions have been successful in limiting PPWR in mothers. The present study assessed the effectiveness of the mums OnLiNE (Online, Lifestyle, Nutrition & Exercise) intervention with respect to reducing PPWR and improving diet, physical activity and sedentary behaviour.

METHODS

A subsample of first-time mothers enrolled in the Extended Melbourne Infant Feeding Activity and Nutrition Trial (InFANT Extend) completed the nonrandomised mums OnLiNE intervention. Women in the intervention (I) group (n = 28) received access to an online calorie tracking program, smartphone app, three telephone counselling calls with a dietitian and written material. Women in two comparison groups (CI and C2) (n = 48; n = 43) were from the control (C1) and intervention (C2) arms of InFANT Extend and received no additional support. Weight and waist circumference were measured objectively. Written surveys assessed diet and physical activity. Sedentary behaviour was self-reported. Linear and logistic regression assessed changes in outcomes between groups from 9 to 18 months postpartum.

RESULTS

Mean PPWR decreased in the (I) group (-1.2 kg) and the C2 group (-1.2 kg), although the changes were not significant. Mean waist circumference for all groups exceeded recommendations at baseline but decreased to below recommendations for women in the (I) group (78.3 cm) and significantly for the (I) group (-6.4 cm) compared to C1 (-1.1 cm; P = 0.002) and C2 (-3.3 cm; P = 0.001). Changes in diet, physical activity or sedentary behaviour were not significant.

CONCLUSIONS

The online intervention reported in the present study shows promise with respect to reducing waist circumference in postpartum women. Further evidence of strategies that may improve weight and related behaviours in this target group is needed.

The views of first time mothers completing an intervention to reduce postpartum weight retention: A qualitative evaluation of the mums OnLiNE study

BACKGROUND

maternal postpartum weight retention (PPWR) has implications for short and long term weight-related health of both the mother and child. Little is known about how mothers perceive they may be best supported to achieve a healthy postpartum weight and healthy lifestyle behaviours. Evaluating existing postpartum weight focussed intervention strategies is an important step in the planning of future programs aimed at supporting new mothers.

AIM

to describe the perspectives of women who completed the mums OnLiNE pilot intervention, regarding the acceptability and effectiveness of a program which aimed to limit PPWR and promote healthy diet and physical activity behaviours in new mothers.

METHOD

descriptive qualitative research methods utilising semi-structured interview questions to explore new mothers' views regarding their participation in the mums OnLiNE intervention were used. All women who completed the intervention were invited to participate in one-on-one interviews via telephone. Interviews were digitally recorded and transcribed verbatim. Data were analysed utilising thematic analysis for common, emerging themes.

FINDINGS

twelve women participated in the interviews. Six main themes including program usefulness, intervention components, walking, self-monitoring, barriers and challenges and future recommendations described women's views of the mums OnLiNE intervention. Women felt well supported being part of the program and their reported awareness of healthy eating increased. Telephone support was the most valued and helpful component of the intervention and the smartphone application for self-monitoring was used more often than the website. Walking was by far the most preferred activity as it was considered enjoyable and achievable and some reported that their incidental walking increased as a result of being part of the program. Lack of time and motivation were the main barriers to participation in the program. Suggestions for future programs included encouraging group support and mother-baby exercise sessions.

CONCLUSION

women perceived the mums OnLiNE intervention to be useful in promoting a healthy lifestyle and valued the support provided. Whilst barriers to participation in healthy lifestyle programs exist, well planned interventions which consider time constraints of new mothers, utilize one-on-one support and offer social engagement with other new mothers may further support women in their attainment of healthy postpartum weight and lifestyle behaviours.

Is the link between movement and mental health a two-way street? Prospective associations between physical activity, sedentary behaviour and depressive symptoms among women living in socioeconomically disadvantaged neighbourhoods

This study aimed to investigate the bi-directional relationship between different domains of physical activity (PA), sedentary behaviour (SB) and depressive symptoms among women living in socioeconomically disadvantaged neighbourhoods in Victoria, Australia. Women (n=1033), aged 18-46years at Wave 1 (2007/08), completed self-report measures of PA (leisure-time, transport, occupational, domestic), SB (TV viewing, computer use, overall sitting time) and depressive symptoms (CES-D 10) at each study time-point (Wave 2: 2010/11, Wave 3: 2012/13). Separate linear mixed models were fitted to examine if change in depressive symptoms differed dependent on each of the baseline PA or SB measures. Similarly, baseline depressive symptoms were used as a predictor of change in PA and SB. In secondary analyses, associations between baseline PA or SB and odds of becoming 'at risk' of depression among those not 'at risk' at baseline were examined using logistic regression. There was no evidence that change in depressive symptoms differed depending on PA or SB at baseline. In general, there was also no evidence that change in PA or SB differed depending on baseline depressive symptoms. One exception was change in leisure-time PA, which declined more among those with heightened depressive symptoms at baseline (Interaction: β=-0.003, 95% CI=-0.007, -0.0003). Transport-related PA (adjusted OR=1.06, 95% CI=1.013, 1.101) and domestic PA (adjusted OR=1.02, 95% CI=1.003, 1.040) were associated with greater odds of becoming at risk of depression at wave 3. There was limited evidence of a bi-directional relationship between PA, SB and depressive symptoms in women living in socioeconomically disadvantaged neighbourhoods.

Effectiveness of interventions to promote physical activity and/or decrease sedentary behaviour among rural adults: a systematic review and meta-analysis

Physical inactivity and overweight and obesity are more prevalent among rural than urban populations. This study aimed to review published evidence of the effectiveness of interventions to increase physical activity (PA) and/or decrease sedentary behaviour (SB) among rural adults and to identify factors associated with effectiveness. Seven electronic databases were searched for controlled trials of a PA or SB intervention. Meta-analysis was conducted using random effects models and meta-regression. Thirteen studies were included in the qualitative synthesis (n = 4,848 participants) and 12 in the meta-analysis (n = 4,820). All studies were interventions to increase PA. Overall, there was no effect on PA (standardized mean difference [SMD] 0.11; 95% confidence interval [CI] -0.04, 0.25) or SB (SMD 0.07; 95% CI -0.33, 0.20). In PA subgroup analyses, studies employing objective outcome measures demonstrated effects in favour of the intervention (SMD 0.65, 95% CI 0.30, 1.00), while those using self-reported measures did not (SMD 0.00; 95% CI -0.11, 0.10). This review highlights significant gaps in our understanding of how best to promote PA and reduce SB among rural adults. Future studies should use objective measures of PA as study outcomes. The absence of interventions to decrease SB is of concern, with immediate action required to address this large knowledge gap.

Can targeted policies reduce obesity and improve obesity-related behaviours in socioeconomically disadvantaged populations? A systematic review

This review synthesized evidence from controlled studies pertaining to the impact of targeted policies on anthropometric, dietary and physical activity outcomes amongst socioeconomically disadvantaged children and adults. Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Equity guidelines were followed. Eligible studies were published from 2004 to August 2015 and examined the impact of targeted policies on anthropometric, dietary and physical activity outcomes amongst socioeconomically disadvantaged populations. Twenty articles (18 studies) were included. Eight studies examined organizational policies within multi-component interventions in schools. Common elements of successful policy-containing interventions included nutritional standards, enhancements to physical education, additional physical activity opportunities, school self-assessments, and nutrition and physical activity education. Of the 10 studies of government policies, policies providing information/education and fruit and vegetable subsidies had positive impacts amongst children, but no impact amongst adults. Policies involving changes to built environments yielded nearly uniformly null findings in children and adults. Overall, the largest quantity of high-quality evidence of effectiveness was for comprehensive interventions that included school policies, and government policies targeting disadvantaged children in schools. None of the government policies targeting disadvantaged adults proved effective. Interventions during childhood may ameliorate negative obesity-related manifestations of socioeconomic disadvantage. Gaps in knowledge remain surrounding effective policies in adults, adolescents and very young children.

Impact of the implantable cardioverter defibrillator on confidence to undertake physical activity in inherited heart disease: A cross-sectional study

BACKGROUND

Physical activity is associated with improved quality of life. Patients with an implantable cardioverter defibrillator (ICD) face unique clinical and psychological challenges. Factors such as fear of ICD shock may negatively impact on physical activity, while a sense of protection gained from the ICD may instil confidence to be active.

AIM

We aimed to examine the impact of an ICD on physical activity levels and factors associated with amount of activity.

METHODS

Two cross-sectional studies were conducted. Accelerometer data (seven-day) was collected in March-November 2015 for 63 consecutively recruited hypertrophic cardiomyopathy patients, with or without an ICD, aged ⩾18 years. A survey study was conducted in July-August 2016 of 155 individuals aged ⩾18 years with an inherited heart disease and an ICD in situ.

RESULTS

Based on the International Physical Activity Questionnaire, mean leisure time physical activity was 239 ± 300 min/week with 51% meeting physical activity guidelines. Accelerometry showed that mean moderate-vigorous physical activity was the same for patients with and without an ICD (254 ± 139 min/week versus 300 ± 150 min/week, p=0.23). Nearly half of survey participants ( n=73) said their device made them more confident to exercise. Being anxious about ICD shocks was the only factor associated with not meeting physical activity guidelines.

CONCLUSIONS

Patients with inherited heart disease adjust differently to their ICD device, and for many it has no impact on physical activity. Discussion regarding the appropriate level of physical activity and potential barriers will ensure best possible outcomes in this unique patient group.

Does psychosocial stress explain socioeconomic inequities in 9-year weight gain among young women?

OBJECTIVE

This study investigated the contribution of psychosocial stress to mediating inequities in weight gain by educational status in a large cohort of young Australian women over a 9-year follow-up.

METHODS

This observational cohort study used survey data drawn from 4,806 women, aged 22 to 27 years at baseline (2000), participating in the Australian Longitudinal Study on Women's Health, who reported their education level (2000), perceived stress (2003), and weight (2003 and 2012). Using a causal inference framework based on counterfactuals for mediation analysis, we fitted linear or logistic regression models to examine the total effect, decomposed into natural direct and indirect effects via perceived stress, of education level (highest qualification completed: up to year 12/trade or diploma vs. university) on weight change.

RESULTS

Women with lower education gained more weight over 9 years (6.1 kg, standard deviation [SD] 9.5) than women with higher education (3.8 kg, SD 7.7; P < 0.0001) and were more likely to be very or extremely stressed. The higher weight gain associated with low education was not mediated through perceived stress (per SD increase, percent mediated: 1.0%).

CONCLUSIONS

Education-based inequities in weight gain over time were not attributable to greater psychosocial stress among women with lower education levels.

Cluster randomised controlled trial of a consumer behaviour intervention to improve healthy food purchases from online canteens: study protocol

INTRODUCTION

School canteens represent an opportune setting in which to deliver public health nutrition strategies given their wide reach, and frequent use by children. Online school canteen ordering systems, where students order and pay for their lunch online, provide an avenue to improve healthy canteen purchases through the application of consumer behaviour strategies that impact on purchasing decisions. The aim of this study is to assess the efficacy of a consumer behaviour intervention implemented in an online school canteen ordering system in reducing the kilojoule, saturated fat, sugar and sodium content of primary student lunch orders.

METHODS AND ANALYSIS

The study will employ a cluster randomised controlled trial design. Approximately 1040 students (aged 5-12 years) from 10 primary schools in New South Wales, Australia, currently using an online canteen ordering system will be invited to participate. Schools will be randomised in a 1:1 ratio to receive either the intervention (enhanced system) or control (standard online ordering only). The intervention will include evidence-based strategies shown to influence healthy food purchasing (strategies targeting availability, menu labelling, placement and prompting). The primary outcomes of the trial will be the mean content per student online lunch order of (1) energy (kJ), (2) saturated fat (g), (3) sugar (g) and (4) sodium (mg). The impact of the intervention will be determined by between-group assessment of the nutritional content of lunch purchases over a 2-month period postintervention initiation.

ETHICS AND DISSEMINATION

The study was approved by the Hunter New England Human Research Ethics Committee, University of Newcastle Human Research Ethics Committee and New South Wales Department of Education and School Communities. Study findings will be disseminated widely through peer-reviewed publications and relevant presentations in international conferences and to stakeholders.

TRIAL REGISTRATION NUMBER

ACTRN12616000499482.

Can an incentive-based intervention increase physical activity and reduce sitting among adults? the ACHIEVE (Active Choices IncEntiVE) feasibility study

Background

Despite recent interest in the potential of incentivisation as a strategy for motivating healthier behaviors, little remains known about the effectiveness of incentives in promoting physical activity and reducing sedentary behavior, and improving associated health outcomes.

This pre-post-test design study investigated the feasibility, appeal and effects of providing non-financial incentives for promoting increased physical activity, reduced sedentary time, and reduced body mass index (BMI) and blood pressure among inactive middle-aged adults.

Methods

Inactive men (n = 36) and women (n = 46) aged 40–65 years were recruited via a not-for-profit insurance fund and participated in a 4 month pre-post design intervention. Baseline and post-intervention data were collected on self-reported physical activity and sitting time (IPAQ-Long), BMI and blood pressure. Participants were encouraged to increase physical activity to 150 mins/week and reduce sedentary behavior by 150 mins/week in progressive increments. Incentives included clothing, recipe books, store gift vouchers, and a chance to win one of four Apple iPad Mini devices. The incentive component of the intervention was supported by an initial motivational interview and text messaging to encourage participants and provide strategies to increase physical activity and reduce sedentary behaviors.

Results

Only two participants withdrew during the program, demonstrating the feasibility of recruiting and retaining inactive middle-aged participants. While two-thirds of the sample qualified for the easiest physical activity incentive (by demonstrating 100 mins physical activity/week or 100 mins reduced sitting time/week), only one third qualified for the most challenging incentive. Goals to reduce sitting appeared more challenging, with 43% of participants qualifying for the first incentive, but only 20% for the last incentive. More men than women qualified for most incentives. Mean leisure-time physical activity increased by 252 mins/week (leisure-time), with 65% of the sample achieving at least 150 mins/week; and sitting time decreased by 3.1 h/day (both p < 0.001) between baseline and follow-up. BMI, systolic and diastolic (men only) blood pressure all significantly decreased. Most participants (50–85%) reported finding the incentives and other program components helpful/motivating.

Conclusions

Acknowledging the uncontrolled design, the large pre-post changes in behavioral and health-related outcomes suggest that the ACHIEVE incentives-based behavior change program represents a promising approach for promoting physical activity and reducing sitting, and should be tested in a randomized controlled trial.

Trial registration

Australian New Zealand Clinical Trials Registry IDACTRN12616000158460, registered 10/2/16.

Do intrapersonal factors mediate the association of social support with physical activity in young women living in socioeconomically disadvantaged neighbourhoods? A longitudinal mediation analysis

Background

Levels of physical activity (PA) decrease when transitioning from adolescence into young adulthood. Evidence suggests that social support and intrapersonal factors (self-efficacy, outcome expectations, PA enjoyment) are associated with PA. The aim of the present study was to explore whether cross-sectional and longitudinal associations of social support from family and friends with leisure-time PA (LTPA) among young women living in disadvantaged areas were mediated by intrapersonal factors (PA enjoyment, outcome expectations, self-efficacy).

Methods

Survey data were collected from 18–30 year-old women living in disadvantaged suburbs of Victoria, Australia as part of the READI study in 2007–2008 (T0, N = 1197), with follow-up data collected in 2010–2011 (T1, N = 357) and 2012–2013 (T2, N = 271). A series of single-mediator models were tested using baseline (T0) and longitudinal data from all three time points with residual change scores for changes between measurements.

Results

Cross-sectional analyses showed that social support was associated with LTPA both directly and indirectly, mediated by intrapersonal factors. Each intrapersonal factor explained between 5.9–37.5% of the associations. None of the intrapersonal factors were significant mediators in the longitudinal analyses.

Conclusions

Results from the cross-sectional analyses suggest that the associations of social support from family and from friends with LTPA are mediated by intrapersonal factors (PA enjoyment, outcome expectations and self-efficacy). However, longitudinal analyses did not confirm these findings.

Effect of a price discount and consumer education strategy on food and beverage purchases in remote Indigenous Australia: a stepped-wedge randomised controlled trial

BACKGROUND

Evidence is mounting that price discounts can be effective in improving diet. This study examined the effectiveness of a 20% price discount on food and drink purchases with and without consumer education in remote Indigenous Australia.

METHODS

A 20% discount on fruit, vegetables, water, and artificially sweetened soft drinks was applied for 24 weeks in 20 communities in remote Indigenous Australia where the community store was managed by the Arnhem Land Progress Aboriginal Corporation (ALPA) or Outback Stores (OBS) in a stepped-wedge randomised trial. Communities were randomly allocated to a fixed framework of five sets of four stratified by store association; ten stores (two in each set) were randomly assigned to receive consumer education. A store from each of the ALPA and OBS store groups (contained in separate opaque envelopes) was selected, and stores in turn continued to be consecutively allocated to the fixed store set framework, starting with the first store slot in the first store set, until all stores had been allocated. The effect of the discount on the weight of fruit and vegetables purchased (the primary endpoint) was assessed using weekly store sales data and mixed models per protocol. We did sensitivity analyses by repeating the analyses with the outliers included and repeating the analyses for the primary outcome measure removing each store one at a time. This trial was registered with Australian New Zealand Clinical Trials Registry, number ACTRN12613000694718.

FINDINGS

Weekly store sales data on all food and drink products sold in 20 stores were collected from July 1, 2012, to Dec 28, 2014. Price discount alone was associated with a 12·7% (95% CI 4·1-22·1) increase in purchases in grams of fruit and vegetables combined (primary outcome), and a 19·8% (6·2-35·1) increase post discount (after vs before); an effect of 12 g and 18 g per capita per day. Sensitivity analyses did not modify the results for the primary outcome measure.

INTERPRETATION

A 20% discount can only increase fruit and vegetable purchases to help protect against obesity and diet related disease to a certain extent. Large discounts might have a greater impact than small discounts. Creative merchandising approaches to consumer education could also be considered alongside fiscal interventions to achieve marked improvements in diet.

FUNDING

Australian National Health and Medical Research Council.

A cluster-randomised controlled trial to promote physical activity in adolescents: the Raising Awareness of Physical Activity (RAW-PA) Study

Background

Recent technological advances provide an alternative yet underutilised opportunity for promoting physical activity in youth. The primary aim of the Raising Awareness of Physical Activity (RAW-PA) Study is to examine the short- and longer-term impact of a wearable activity monitor combined with digital behaviour change resources on adolescents’ daily physical activity levels.

Methods/Design

RAW-PA is a 12 week, multicomponent physical activity intervention that utilises a popular activity tracker (Fitbit® Flex) and supporting digital materials that will be delivered online via social media. The resources target key behaviour change techniques. The intervention structure and components have been informed by participatory research principles. RAW-PA will be evaluated using a cluster randomised controlled trial design with schools as the unit of randomisation. Twelve schools located in Melbourne, Australia, will allocated to either the intervention or wait-list control group. The target sample size is 300 Year 8 adolescents (aged 13–14 years). Participants’ moderate- to vigorous-intensity physical activity will be the primary outcome. Survey measures will be completed. Process factors (e.g. feasibility, acceptability/appeal, fidelity) will also be collected.

Discussion

To our knowledge, this study will provide some of the first evidence concerning the effect of wearable activity trackers and digital behaviour change resources on adolescents’ physical activity levels. This study will provide insights into the use of such technologies for physical activity promotion, which may have a significant impact on health education, promotion, practice and policy.

Trial registration

Australian and New Zealand Clinical Trials Registry No: ACTRN12616000899448. Date of registration: July 7, 2016.